That has some easy explanations:
Explaining it doesn't mean it was a good idea. I could explain why I put salt instead of brown sugar in my last batch of cookies, but brown sugar really would've been a better idea.
Besides that, some of those are too
1) Being locked up together at Arkham tends to blurry the lines separating their personal crusades. After a while, their influence kinda tends to rub on each other, especially after team-ups. This is rather evident in Trial.
This is just lazy storytelling, pure and simple. And lazy = dull. I'd rather hear about a Mad Hatter who is trying to come to terms with his feelings and finding creative uses for his genius rather than a Mad Hatter who is just another criminal distinguished only by his motif and gimmick.
Not to mention, this explanation touches off a long stream of wall-bangers that ultimately lead to the conclusion that the whole Batman mythos is pointless because nothing ever gets resolved for good. Which has always been a pain in my craw about superhero mythos.
2) From a meta view, keping `them rail roaded into their original vendettas would make them just as one-note, if not more. Viewers, specially the young target ones, don't want to see Riddler chasing the same man who originally wronged him time and time again.
This one ultimately amounts to trying to pretend a flaw is not a flaw, but to buy that I have to believe that characters like D'Artagnan, Liu Bei, Skeletor, Ryoga Hibiki, Rin-chan etc. are mishandled and that B:TAS' writers had the right idea. I'm sorry, but I can't see how Ryoga would be more interesting if he was no longer in love with Akane or mad at Ranma for causing his curse, and instead was just a guy who showed up every once in awhile to make Ranma's life miserable, or how Liu Bei would be more interesting if he dropped the whole "wanting to preserve/rebuild the Han Empire" thing and was just a guy who started fights because Luo Guanzhong needed a storyline.
3) Contacts with the gangs and the underworld of crime in general tends to draw them deeper into crime for the sake of crime and beyond their original motives. It (kinda) happens in real life, too.
Draws on the assumption that anyone who does any illegal activity is arch-criminal material and that there's no difference between "guy who made a bad decision in a tense moment" and "lawyer with repressed anger who was in a traumatic accident." In realistic terms, there's no way the former would end up in exactly the same place as the latter. That takes some pretty deterministic thinking.
4) Their revenge schemes demand for a lot of money, and simply, that money must be got some way.
Is everyone in it for revenge? Is there only one kind of revenge scheme and they're all really expensive? I've seen crime shows of wives who had hits put on their husbands, and these people didn't need to rob banks to do it.
5) After a while, through Batman's continued interference, they tend to displace their aggression and putting the blame on everything on him (and society in general, sometimes).
So every single criminal Batman faces is ultimately going to end up having the same personality, just with different clothing and gimmicks. That's the problem.
edited 7th Mar '11 12:32:08 PM by MoeDantes